Systems and methods for leak detection and management in heating, ventilating, and air conditioning (hvac) systems

ABSTRACT

A heating, ventilation, and air conditioning (HVAC) system includes multiple circuit components that enable determining that a refrigerant leak is present in the HVAC system based on a signal. The circuit components then send a first set of instructions to a first set of control systems associated with one or more fans in response to the refrigerant leak being present. The first set of instructions causes the one or more fans to activate. The system then determines that the refrigerant leak signal is no longer present, and initiates a counter to detect when a period of time has passed in response to determining that the refrigerant leak signal is no longer present. The system then sends a second set of instructions to the first control system to cause the fans to return to base operating conditions in response to the counter indicating the period of time has passed.

BACKGROUND

The present disclosure relates generally to heating, ventilating, andair conditioning (HVAC) systems, and more particularly to refrigerantleak management for HVAC systems.

Residential, light commercial, commercial, and industrial HVAC systemsare used to control temperatures and air quality in residences andbuildings. Generally, the HVAC systems may circulate a refrigerantthrough a closed refrigeration circuit between an evaporator, where therefrigerant absorbs heat, and a condenser, where the refrigerantreleases heat. The refrigerant flowing within the circuit is generallyformulated to undergo phase changes within the normal operatingtemperatures and pressures of the system so that quantities of heat canbe exchanged by virtue of the latent heat of vaporization of therefrigerant. As such, the refrigerant flowing within a HVAC systemtravels through multiple conduits and components of the circuit.Inasmuch as refrigerant leaks compromise system performance or result inincreased costs, it is accordingly desirable to provide detection andresponse systems and methods for the HVAC system to reliably detect andrespond to any refrigerant leaks of the HVAC system.

This section is intended to introduce the reader to various aspects ofart that may be related to various aspects of the present techniques,which are described and/or claimed below. This discussion is believed tobe helpful in providing the reader with background information tofacilitate a better understanding of the various aspects of the presentdisclosure. Accordingly, it should be understood that these statementsare to be read in this light, and not as admissions of prior art.

SUMMARY

A summary of certain embodiments disclosed herein is set forth below. Itshould be understood that these aspects are presented merely to providethe reader with a brief summary of these certain embodiments and thatthese aspects are not intended to limit the scope of this disclosure.Indeed, this disclosure may encompass a variety of aspects that may notbe set forth below.

In one embodiment, a system includes a heating ventilation and airconditioning (HVAC) system and circuit components that are configured todetermine a refrigerant leak is present within an HVAC system based on asignal. The circuitry components are then configured to send a first setof instructions to a first set of control systems associated with one ormore fans in response to the refrigerant leak being present.Additionally, the first set of instructions is configured to cause theone or more fans to activate. The circuit components are then configuredto determine that the refrigerant leak signal is no longer present basedon the signal and initiate a counter to detect when a period of time haspassed, in response to determining that the refrigerant leak signal isno longer present. Further, the circuit component are configured to senda second set of instructions to the first set of control systems, inresponse to the counter indicating that the period of time has passed.The second set of instructions is then configured to cause the one ormore fans to return to base operating conditions.

In another embodiment, an integrated circuit includes a plurality ofcircuit components that are configured to detect that a signalcorresponding to a refrigerant leak is present, and send a first set ofinstructions to a first control system associated with one or more fansin response to the refrigerant leak being present. The first set ofinstructions is configured to cause the one or more fans to activate.The circuit components are then configured to determine that therefrigerant leak signal is no longer present based on the signal andinitiate a counter to detect when a period of time has passed inresponse to determining that the refrigerant leak signal is no longerpresent. Additionally, the circuit components are configured to send asecond set of instructions to the first set of control systems inresponse to the counter indicating that the period of time has passed,and the second instructions are configured to cause the one or more fansto return to base operating conditions.

In an additional embodiment, a set of hardware components are configuredto receive a refrigerant leak signal from a sensor assembly, andtransmit a leak detection signal and pre-set a counter in response toreceiving the refrigerant leak signal. Further, the set of hardwarecomponents are configured to determine that the refrigerant leak signalis no longer being received. The hardware components are then configuredto transmit the leak detection signal after a delay period of time afterthe refrigerant leak signal is no longer received, and in response tothe counter indicating that the delay period of time has passed.

In a further embodiment, a method includes determining that a signalcorresponding to a refrigerant leak is present and sending a first setof instructions to a first set of control systems associated with one ormore fans, in response to the refrigerant leak being present.Additionally, the first set of instructions is configured to cause oneor more fans to activate. Further, the method includes initiating acounter to detect when a period of time has passed in response todetermining that the refrigerant leak signal is no longer present, andsending a second set of instructions to the first set of controlsystems, in response to the counter indicating that the period of timehas passed. The second set of instructions is then configured to causethe one or more fans to return to base operating conditions.

Other features and advantages of the present application will beapparent from the following, more detailed description of theembodiments, taken in conjunction with the accompanying drawings whichillustrate, by way of example, the principles of the application.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects, and advantages of the embodimentsdescribed in the present disclosure will become better understood whenthe following detailed description is read with reference to theaccompanying drawings in which like characters represent like partsthroughout the drawings, wherein:

FIG. 1 is an illustration of an embodiment of a commercial or industrialHVAC system, in accordance with present techniques;

FIG. 2 is an illustration of an embodiment of a packaged unit of theHVAC system, in accordance with present techniques;

FIG. 3 is an illustration of an embodiment of a split system of the HVACsystem, in accordance with present techniques;

FIG. 4 is a schematic diagram of an embodiment of a refrigeration systemof the HVAC system, in accordance with present techniques;

FIG. 5 is a flowchart of a method of refrigerant leak detection andmitigation for the refrigeration system of FIG. 4 , in accordance withpresent techniques;

FIG. 6 is a graphical representation of various signal outputs for arefrigerant leak detection and mitigation system, in accordance withpresent techniques;

FIG. 7A is an example schematic diagram of components of control logicincluding a counter pre-set and clock component for the refrigerant leakdetection and mitigation system of FIG. 6 , in accordance with presenttechniques;

FIG. 7B is an example schematic diagram of components of control logicincluding a counter component for the refrigerant leak detection andmitigation system of FIG. 6 , in accordance with present techniques;

FIG. 7C is an example schematic diagram of components of control logicincluding output lockout logic components for the refrigerant leakdetection and mitigation system of FIG. 6 , in accordance with presenttechniques; and

FIG. 8 is an example schematic diagram of the output lockout logic ofthe control logic of FIGS. 7A-7C, in accordance with the presenttechniques.

DETAILED DESCRIPTION

One or more specific embodiments of the present disclosure will bedescribed below. In an effort to provide a concise description of theseembodiments, all features of an actual implementation may not bedescribed in the specification. It should be appreciated that in thedevelopment of any such actual implementation, as in any engineering ordesign project, numerous implementation-specific decisions must be madeto achieve the developers' specific goals, such as compliance withsystem-related and business-related constraints, which may vary from oneimplementation to another. Moreover, it should be appreciated that sucha development effort might be complex and time consuming, but wouldnevertheless be a routine undertaking of design, fabrication, andmanufacture for those of ordinary skill having the benefit of thisdisclosure. When introducing elements of various embodiments of thepresent disclosure, the articles “a,” “an,” “the,” and “said” areintended to mean that there are one or more of the elements. The terms“comprising,” “including,” and “having” are intended to be inclusive andmean that there may be additional elements other than the listedelements.

As discussed above, a HVAC system generally includes a refrigerantflowing within a refrigeration system. However, the refrigerant mayinadvertently leak from a flow path of the refrigeration system due towear or damage to components, faulty joints, or connections within therefrigeration system at some point after installation. If undetected,leaking refrigerant may compromise system performance or result inincreased costs. As such, present techniques enable HVAC systems toreliably detect and manage refrigerant leaks.

With the foregoing in mind, present embodiments are directed to arefrigerant leak management system that is capable of detecting and/ormitigating refrigerant leaking from a refrigeration circuit of a HVACsystem. The disclosed refrigerant leak management system includes leakmitigation hardware logic that includes an oscillator generating aclock, a resettable down counter with pre-load functionality, and alogic array that may implement override output logic conditions. Theoverride output logic conditions may correspond to industry standards(e.g., ASHRAE 15-2019). Sensors of the HVAC system may detect arefrigerant leak and may send a signal to the leak mitigation hardwarelogic to indicate that a leak has occurred. In response to receiving arefrigerant leak detection signal, the leak mitigation hardware logicmay shut off compressors and electrical devices and continue operatingthe supply air fan for a specified duration (e.g., delay time periodcorresponding the regulatory standards) after the leak refrigerantdetector has sensed a drop in refrigerant concentration and therefrigerant leak detection signal is no longer present. In this way, thesupply fan may function to purge the leaked refrigerant from theequipment enclosure into the external environment until the leakedrefrigerant concentration has dropped below a threshold concentration.The compressors and electrical devices may be shut off until the leak isno longer present to avoid operating while the refrigerant leak ispresent.

Turning now to the drawings, FIG. 1 illustrates a heating, ventilating,and air conditioning (HVAC) system for building environmental managementthat may employ one or more HVAC units. In the illustrated embodiment, abuilding 10 is air conditioned by a system that includes a HVAC unit 12.The building 10 may be a commercial structure or a residentialstructure. As shown, the HVAC unit 12 is disposed on the roof of thebuilding 10; however, the HVAC unit 12 may be located in other equipmentrooms or areas adjacent to the building 10. The HVAC unit 12 may be asingle package unit containing other equipment, such as a blower,integrated air handler, and/or auxiliary heating unit. In otherembodiments, the HVAC unit 12 may be part of a split HVAC system, suchas the system shown in FIG. 3 , which includes an outdoor HVAC unit 58and an indoor HVAC unit 56.

The HVAC unit 12 is an air cooled device that implements a refrigerationcycle to provide conditioned air to the building 10. Specifically, theHVAC unit 12 may include one or more heat exchangers across which an airflow is passed to condition the air flow before the air flow is suppliedto the building. In the illustrated embodiment, the HVAC unit 12 is arooftop unit (RTU) that conditions a supply air stream, such asenvironmental air and/or a return air flow from the building 10. Afterthe HVAC unit 12 conditions the air, the air is supplied to the building10 via ductwork 14 extending throughout the building 10 from the HVACunit 12. For example, the ductwork 14 may extend to various individualfloors or other sections of the building 10. In certain embodiments, theHVAC unit 12 may be a heat pump that provides both heating and coolingto the building with one refrigeration circuit configured to operate indifferent modes. In other embodiments, the HVAC unit 12 may include oneor more refrigeration circuits for cooling an air stream and a furnacefor heating the air stream.

A control device 16, one type of which may be a thermostat, may be usedto designate the temperature of the conditioned air. The control device16 also may be used to control the flow of air through the ductwork 14.For example, the control device 16 may be used to regulate operation ofone or more components of the HVAC unit 12 or other components, such asdampers and fans, within the building 10 that may control flow of airthrough and/or from the ductwork 14. In some embodiments, other devicesmay be included in the system, such as pressure and/or temperaturetransducers or switches that sense the temperatures and pressures of thesupply air, return air, and so forth. Moreover, the control device 16may include computer systems that are integrated with or separate fromother building control or monitoring systems, and even systems that areremote from the building 10.

FIG. 2 is a perspective view of an embodiment of the HVAC unit 12. Inthe illustrated embodiment, the HVAC unit 12 is a single package unitthat may include one or more independent refrigeration circuits andcomponents that are tested, charged, wired, piped, and ready forinstallation. The HVAC unit 12 may provide a variety of heating and/orcooling functions, such as cooling only, heating only, cooling withelectric heat, cooling with dehumidification, cooling with gas heat, orcooling with a heat pump. As described above, the HVAC unit 12 maydirectly cool and/or heat an air stream provided to the building 10 tocondition a space in the building 10.

As shown in the illustrated embodiment of FIG. 2 , a cabinet 24 enclosesthe HVAC unit 12 and provides structural support and protection to theinternal components from environmental and other contaminants. In someembodiments, the cabinet 24 may be constructed of galvanized steel andinsulated with aluminum foil faced insulation. Rails 26 may be joined tothe bottom perimeter of the cabinet 24 and provide a foundation for theHVAC unit 12. In certain embodiments, the rails 26 may provide accessfor a forklift and/or overhead rigging to facilitate installation and/orremoval of the HVAC unit 12. In some embodiments, the rails 26 may fitinto “curbs” on the roof to enable the HVAC unit 12 to provide air tothe ductwork 14 from the bottom of the HVAC unit 12 while blockingelements such as rain from leaking into the building 10.

The HVAC unit 12 includes heat exchangers 28 and 30 in fluidcommunication with one or more refrigeration circuits. Tubes within theheat exchangers 28 and 30 may circulate refrigerant through the heatexchangers 28 and 30. For example, the refrigerant may be A2Lrefrigerants or any other suitable refrigerants. The tubes may be ofvarious types, such as multichannel tubes, conventional copper oraluminum tubing, and so forth. Together, the heat exchangers 28 and 30may implement a thermal cycle in which the refrigerant undergoes phasechanges and/or temperature changes as it flows through the heatexchangers 28 and 30 to produce heated and/or cooled air. For example,the heat exchanger 28 may function as a condenser where heat is releasedfrom the refrigerant to ambient air, and the heat exchanger 30 mayfunction as an evaporator where the refrigerant absorbs heat to cool anair stream. In other embodiments, the HVAC unit 12 may operate in a heatpump mode where the roles of the heat exchangers 28 and 30 may bereversed. That is, the heat exchanger 28 may function as an evaporatorand the heat exchanger 30 may function as a condenser. In furtherembodiments, the HVAC unit 12 may include a furnace for heating the airstream that is supplied to the building 10. While the illustratedembodiment of FIG. 2 shows the HVAC unit 12 having two of the heatexchangers 28 and 30, in other embodiments, the HVAC unit 12 may includeone heat exchanger or more than two heat exchangers.

The heat exchanger 30 is located within a compartment 31 that separatesthe heat exchanger 30 from the heat exchanger 28. Fans 32 draw air fromthe environment through the heat exchanger 28. Air may be heated and/orcooled as the air flows through the heat exchanger 28 before beingreleased back to the environment surrounding the rooftop unit 12. Ablower assembly 34, powered by a motor 36, draws air through the heatexchanger 30 to heat or cool the air. The heated or cooled air may bedirected to the building 10 by the ductwork 14, which may be connectedto the HVAC unit 12. Before flowing through the heat exchanger 30, theconditioned air flows through one or more filters 38 that may removeparticulates and contaminants from the air. In certain embodiments, thefilters 38 may be disposed on the air intake side of the heat exchanger30 to prevent contaminants from contacting the heat exchanger 30.

The HVAC unit 12 also may include other equipment for implementing thethermal cycle. Compressors 42 increase the pressure and temperature ofthe refrigerant before the refrigerant enters the heat exchanger 28. Thecompressors 42 may be any suitable type of compressors, such as scrollcompressors, rotary compressors, screw compressors, or reciprocatingcompressors. In some embodiments, the compressors 42 may include a pairof hermetic direct drive compressors arranged in a dual stageconfiguration 44. However, in other embodiments, any number of thecompressors 42 may be provided to achieve various stages of heatingand/or cooling. As may be appreciated, additional equipment and devicesmay be included in the HVAC unit 12, such as a solid-core filter drier,a drain pan, a disconnect switch, an economizer, pressure switches,phase monitors, and humidity sensors, among other things.

The HVAC unit 12 may receive power through a terminal block 46. Forexample, a high voltage power source may be connected to the terminalblock 46 to power the equipment. The operation of the HVAC unit 12 maybe governed or regulated by a control board 48. The control board 48 mayinclude control circuitry connected to a thermostat, sensors, andalarms. One or more of these components may be referred to hereinseparately or collectively as the control device 16. The controlcircuitry may be configured to control operation of the equipment,provide alarms, and monitor safety switches. Wiring 49 may connect thecontrol board 48 and the terminal block 46 to the equipment of the HVACunit 12.

FIG. 3 illustrates a residential heating and cooling system 50, also inaccordance with present techniques. The residential heating and coolingsystem 50 may provide heated and cooled air to a residential structure,as well as provide outside air for ventilation and provide improvedindoor air quality (IAQ) through devices such as ultraviolet lights andair filters. In the illustrated embodiment, the residential heating andcooling system 50 is a split HVAC system. In general, a residence 52conditioned by a split HVAC system may include refrigerant conduits 54that operatively couple the indoor unit 56 to the outdoor unit 58. Theindoor unit 56 may be positioned in a utility room, an attic, abasement, and so forth. The outdoor unit 58 is typically situatedadjacent to a side of residence 52 and is covered by a shroud to protectthe system components and to prevent leaves and other debris orcontaminants from entering the unit. The refrigerant conduits 54transfer refrigerant between the indoor unit 56 and the outdoor unit 58,typically transferring primarily liquid refrigerant in one direction andprimarily vaporized refrigerant in an opposite direction.

When the system shown in FIG. 3 is operating as an air conditioner, aheat exchanger 60 in the outdoor unit 58 serves as a condenser forre-condensing vaporized refrigerant flowing from the indoor unit 56 tothe outdoor unit 58 via one of the refrigerant conduits 54. In theseapplications, a heat exchanger 62 of the indoor unit functions as anevaporator. Specifically, the heat exchanger 62 receives liquidrefrigerant, which may be expanded by an expansion device, andevaporates the refrigerant before returning it to the outdoor unit 58.

The outdoor unit 58 draws environmental air through the heat exchanger60 using a fan 64 and expels the air above the outdoor unit 58. Whenoperating as an air conditioner, the air is heated by the heat exchanger60 within the outdoor unit 58 and exits the unit at a temperature higherthan it entered. The indoor unit 56 includes a blower or fan 66 thatdirects air through or across the indoor heat exchanger 62, where theair is cooled when the system is operating in air conditioning mode.Thereafter, the air is passed through ductwork 68 that directs the airto the residence 52. The overall system operates to maintain a desiredtemperature as set by a system controller. When the temperature sensedinside the residence 52 is higher than the set point on the thermostat,or the set point plus a small amount, the residential heating andcooling system 50 may become operative to refrigerate additional air forcirculation through the residence 52. When the temperature reaches theset point, or the set point minus a small amount, the residentialheating and cooling system 50 may stop the refrigeration cycletemporarily.

The residential heating and cooling system 50 may also operate as a heatpump. When operating as a heat pump, the roles of heat exchangers 60 and62 are reversed. That is, the heat exchanger 60 of the outdoor unit 58will serve as an evaporator to evaporate refrigerant and thereby coolair entering the outdoor unit 58 as the air passes over outdoor the heatexchanger 60. The indoor heat exchanger 62 will receive a stream of airblown over it and will heat the air by condensing the refrigerant.

In some embodiments, the indoor unit 56 may include a furnace system 70.For example, the indoor unit 56 may include the furnace system 70 whenthe residential heating and cooling system 50 is not configured tooperate as a heat pump. The furnace system 70 may include a burnerassembly and heat exchanger, among other components, inside the indoorunit 56. Fuel is provided to the burner assembly of the furnace 70 whereit is mixed with air and combusted to form combustion products. Thecombustion products may pass through tubes or piping in a heat exchangerthat is separate from heat exchanger 62, such that air directed by theblower 66 passes over the tubes or pipes and extracts heat from thecombustion products. The heated air may then be routed from the furnacesystem 70 to the ductwork 68 for heating the residence 52.

FIG. 4 is an embodiment of a vapor compression system 72 that can beused in any of the systems described above. The vapor compression system72 may circulate a refrigerant through a set of components include acompressor 74. The set of components may also include a condenser 76, anexpansion valve(s) or device(s) 78, and an evaporator 80. The vaporcompression system 72 may further include a control panel 82 that mayinclude an analog to digital (A/D) converter 83, a microprocessor 86,hardware logic 84, a non-volatile memory 88, and/or an interface board90. The control panel 82 and its components may function to regulateoperation of the vapor compression system 72 based on feedback from anoperator, from sensors of the vapor compression system 72 that detectoperating conditions, and so forth.

In some embodiments, the vapor compression system 72 may include one ormore of a variable speed drive (VSDs) 92, a motor 94, the compressor 74,the condenser 76, the expansion valve or device 78, and/or theevaporator 80. The motor 94 may drive the compressor 74 and may bepowered by the variable speed drive (VSD) 92. The VSD 92 receivesalternating current (AC) power having a particular fixed line voltageand fixed line frequency from an AC power source, and provides powerhaving a variable voltage and frequency to the motor 94. In otherembodiments, the motor 94 may be powered directly from an AC or directcurrent (DC) power source. The motor 94 may include any type of electricmotor that can be powered by a VSD or directly from an AC or DC powersource, such as a switched reluctance motor, an induction motor, anelectronically commutated permanent magnet motor, or another suitablemotor.

The compressor 74 compresses a refrigerant vapor and delivers the vaporto the condenser 76 through a discharge passage. In some embodiments,the compressor 74 may be a centrifugal compressor. The refrigerant vapordelivered by the compressor 74 to the condenser 76 may transfer heat toa fluid passing across the condenser 76, such as ambient orenvironmental air 96. The refrigerant vapor may condense to arefrigerant liquid in the condenser 76 as a result of thermal heattransfer with the environmental air 96. The liquid refrigerant from thecondenser 76 may flow through the expansion device 78 to the evaporator80.

The liquid refrigerant delivered to the evaporator 80 may absorb heatfrom another air stream, such as a supply air stream 98 provided to thebuilding 10 or the residence 52. For example, the supply air stream 98may include ambient or environmental air, return air from a building, ora combination of the two. The liquid refrigerant in the evaporator 80may undergo a phase change from the liquid refrigerant to a refrigerantvapor. In this manner, the evaporator 80 may reduce the temperature ofthe supply air stream 98 via thermal heat transfer with the refrigerant.Thereafter, the vapor refrigerant exits the evaporator 80 and returns tothe compressor 74 by a suction line to complete the cycle.

In some embodiments, the vapor compression system 72 may further includea reheat coil in addition to the evaporator 80. For example, the reheatcoil may be positioned downstream of the evaporator 80 relative to thesupply air stream 98 and may reheat the supply air stream 98 when thesupply air stream 98 is overcooled to remove humidity from the supplyair stream 98 before the supply air stream 98 is directed to thebuilding 10 or the residence 52.

The vapor compression system 72 may include one or more sensorscommunicatively coupled to the control panel 82 to detect refrigerantleak faults and other types of equipment faults (e.g., high-pressurerefrigeration override switches, fan overload). The one or more sensorsmay be any type of sensors, including electrochemical gas detectors,catalytic bead sensors, photoionization detectors, infrared pointsensors, infrared imaging sensors, semiconductor sensors, ultrasonic gasdetectors, holographic gas sensors, pressure sensors or any othersuitable sensors capable of detecting a concentration of the refrigerantand/or detecting high pressure switch trips. Moreover, the refrigerantleak management system may, additionally or alternatively, include othersensors suitable for detecting a presence of the refrigerant, such astemperature sensors, pressure sensors, acoustic sensors, flowratesensors, etc.

In addition to the sensors described above, the control panel 82 may becoupled to a sensor assembly 100 that may include one or morerefrigerant sensors, a microcontroller, and a power supply. The powersupply may be coupled to the microcontroller, and the microcontrollermay provide output logic (e.g., binary output 24 Voltage AnalogConvertor (VAC), Sensor Actuator bus, 4-20 miliamp (mA) signals) to thecontrol panel 82. The microcontroller may receive the one or morerefrigerant sensor signals, and based on the signals, themicrocontroller may determine that the refrigerant leak is present. Forexample, during operation of the HVAC system, a leak of the refrigerantmay not be present when the concentration of the refrigerant 104 isbelow a lower management limit (e.g., lower flame limit perUL60335-2-30). However, when refrigerant leaks from a conduit and isdetected by the one or more refrigerant sensors, the microcontrollerreceives the sensor data and determines that a non-zero concentration ofthe refrigerant is present within the sleeves around the conduits of theHVAC system. As a result, the microcontroller of the sensor assembly 100may then send a refrigerant leak signal to hardware logic 84 of thecontrol panel 82. The hardware logic 84 may include a discrete logicdevice, a complex programmable logic device (CLPD), a field-programmablegate array (FPGA), an application-specific integrated circuit (ASIC), orthe like.

Additionally, the microcontroller of the sensor assembly 100 may comparethe concentration of the refrigerant received from the one or morerefrigerant sensors to a predefined concentration threshold. Thepredefined concentration threshold may be a user-set, technician-set, ordistributor-set value that is stored within the control panel 82, eitherbefore or after the sensor assembly 100 is placed into operation withinthe HVAC system. In response to determining that the concentration ofthe refrigerant is greater than or equal to the predefined concentrationthreshold, the sensor assembly 100 may output a signal to hardware logic84 of the controls system 82 that indicates that a refrigerant leak ispresent in the HVAC system. This enables the operation and/or continuedoperation of the fans to maintain the sub-barometric pressure and otherenables other mitigation measures (e.g., turning off compressors andheaters) to be implemented. In some embodiments, rather thancontinuously measure the one or more refrigerant sensor data themicrocontroller may also wait a predefined time threshold beforedetermining the concentration of the refrigerant again, thus enhancingsensor life. In certain embodiments, the predefined time threshold isset as 1 minute, 5 minutes, 10 minutes, 60 minutes, or any suitablefrequency.

It should be appreciated that any of the features described herein maybe incorporated with the HVAC unit 12, the residential heating andcooling system 50, or other HVAC systems. Additionally, while thefeatures disclosed herein are described in the context of embodimentsthat directly heat and cool a supply air stream provided to a buildingor other load, embodiments of the present disclosure may be applicableto other HVAC systems as well. For example, the features describedherein may be applied to mechanical cooling systems, free coolingsystems, chiller systems, or other heat pump or refrigerationapplications.

As discussed above, the HVAC system generally includes a refrigerantflowing within a refrigeration system. However, the refrigerant mayinadvertently leak from a flow path of the refrigeration system due towear or damage to components, faulty joints, or connections within therefrigeration circuit at some point after installation. If undetected,leaking refrigerant may compromise system performance or result inincreased costs.

With this in mind, the present embodiments described herein incorporatehardware logic 84 to enable the HVAC system to detect a refrigerant leakand perform mitigation measures to reduce the concentration ofrefrigerant within the HVAC system and disperse the refrigerant into theoutside environment via the air supply fan, and suspend compressor andother equipment operations to avoid damage to these components due tothe refrigerant leaks. In this way, the present embodiments may performthe mitigation measures in lieu of employing software and/or firmware tocontrol various operations, thereby providing a more robust and reliablesystem for implementing the mitigation measures.

As discussed above, refrigerant leaks may occur in HVAC systems andcertain mitigation actions relating to industry regulatory standards maybe implemented to activate air supply fans and shut off compressors andelectrical equipment in response to detecting refrigerant leaks. Toimplement these mitigation measures, the HVAC system may employ hardwarelogic 84 to detect refrigerant leaks and automatically shut downcompressors and electrical equipment and activate an air supply fan todisperse the refrigerant according to regulatory standards. With theforegoing in mind, FIG. 5 is a method of refrigerant leak detection andmitigation for the refrigeration system of FIG. 4 , in accordance withthe present disclosure. As will be discussed in more detail below, themethod 110 of refrigerant leak management includes hardware logic 84 ofthe control panel 82 that may detect a refrigerant leak signal andperform suitable control actions to mitigate the leaked refrigerant. Thesuitable control actions to mitigate the leaked refrigerant may bedesignated according to industry safety standards (e.g., ASHRAE15-2019).

Before proceeding, it should be noted that any suitable computing device(e.g., the control panel 82) may control components of the HVAC systemand perform the operations described below with reference to the method110. In some embodiments, the method 110 may be performed by one or morehardware components, such as hardware logic 84 circuits (e.g., outputlockout circuit, 16-bit down counter, and the like) that are part of thecontrol panel 82. While the method 110 is described using steps in aspecific sequence, it should be understood that the present disclosurecontemplates that the described steps may be performed in differentsequences than the sequence illustrated, and certain described steps maybe skipped or not performed altogether.

To begin the illustrated method 110, hardware logic 84 that is part ofthe control panel 82 may, at process block 112, receive a refrigerantleak signal indicative of a detection of a leak of refrigerant from asensor assembly 100. The refrigerant leak signal may be generated by thesensor assembly 100 based on sensor data received from one or morerefrigerant sensors that indicate that the concentration of refrigerantexceeds a threshold value (e.g., compares sensor reading to 25% lowerflame limit). The sensor assembly 100 may then send the refrigerant leaksignal to the control panel 82, and the hardware logic 84 may begin toimplement multiple mitigation processes to disperse leaked refrigerantoutside the HVAC system and avoid damaging equipment within the HVACsystem due to the refrigerant leak.

For example, at process block 114, the hardware logic 84 may sendcontrol instructions to the supply air fan 32 or a controller thatcontrols operations of the supply air fan 32 to operate at apredetermined speed or rotational rate in response to receiving therefrigerant leak signal. Additionally, the hardware logic 84 may sendinstructions to the one or more compressors 74 to power down in responseto the refrigerant leak signal detection. Moreover, the hardware logic84 may send the instructions to any heaters and/or electrical deviceslocated in the ductwork of the HVAC system to power down. It should beunderstood that the hardware logic 84 may send commands to any componentof the HVAC system to comply with regulatory standards for performingrefrigerant leak mitigation and should not be limited to the commandsdescribed herein.

At process block 116, the hardware logic 84 may determine whether therefrigerant leak is still present based on whether the refrigerant leaksignal (e.g., high signal) is still being received from the sensorassembly 100. If the hardware logic 84 determines that the refrigerantleak signal is still present, the hardware logic may return to block116. That is, the hardware logic 84 may not modify the operations of thefans, the compressors, or other equipment because the refrigerant leakis still present. As such, the supply fan may remain active and theheaters, compressors 72, and/or other electrical devices located in theductwork of the HVAC system may be inactive.

Returning to block 116, if the hardware logic 84 determines that therefrigerant leak signal is no longer being received, the hardware logic84 may implement a time delay countdown to wait before modifyingoperations of the devices accessed at block 114. If the time delaycountdown has completed and a certain amount of delay period of time hasexpired, the hardware logic 84 may proceed to block 122 and send updatedinstructions to controllers to return to non-fault operations (e.g.,perform normal operations based on control signals present whenrefrigerant leak signal is no longer received) that control theoperations of the supply air fan 32, the one or more compressors 72, andother devices. That is, if the delay period of time has expired, thehardware logic 84 may proceed to block 122 and may return to non-faultoperations, the normal operations may involve updated instructions beingsent to the supply air fan 32 to deactivate and updated instructions tothe one or more compressors 72 and other devices to activate based oncontrol signals related to non-fault operations. The time delaycountdown may be implemented via the control logic utilizing anysuitable hardware control logic (e.g., 16-bit down counter withpre-load). The counter may be pre-set to a delay value corresponding toindustry regulatory requirements.

For example, the delay value may be set according to ASHRAE 15-2019fault standards, which specify the air supply fan should be activatedfor a minimum of five minutes after the sensor assembly 100 has sensed adrop in refrigerant concentration below a specified value. In the samemanner, the ASHRAE 15-2019 fault standards may specify that the one ormore compressors 72 and one or more heaters should remain deactivatedfor a minimum of five minutes after the refrigerant concentration is nolonger below the threshold value. Although the period of time isdescribed above with reference to the ASHRAE 15-2019 fault standards, itshould be noted that the time delay may be updated to reflect anyregulatory standards or suitable time period specified by an individualor user.

This method enables the HVAC system to implement mitigation actions whena refrigerant leak signal is detected that corresponds to industrystandards in response to a refrigerant leak utilizing hardware logic 84located in the control panel 82. The method mitigates the use ofsoftware programs and/or other mitigation methods to be programmed intothe control panel 82. The hardware logic 84 may also enable greaterreliability than software programs for mitigation of refrigerant leaks.

With the forgoing in mind, FIG. 6 is a graphical representation 130 ofvarious signal outputs for a refrigerant leak detection and mitigationsystem, in accordance with present techniques. The hardware logic 84 ofthe HVAC system may transmit signals to one or more compressors 72, oneor more heaters, and the hardware logic 84 in response to detecting arefrigerant leak signal. These signals may correspond to specificregulatory guidelines determined for refrigerant leaks in HVAC systems,such as the ASHRAE 15-2019 fault standards discussed above.

The graphical representation 130 includes time on the horizontal axisand signal strength and/or counter value on the vertical axis. Thegraphical representation 130 includes the refrigerant leak signal 132over time (e.g., due to detected refrigerant leak) received at thehardware logic 84 of the control panel 82 in response to the sensorassembly 100 detecting a refrigerant leak. The graphical representation130 also includes a leak override signal 134, which is activated (e.g.,high signal value) via hardware logic 84 elements in response todetecting the presence of the refrigerant leak signal 132. The leakoverride signal 134 is high for the time duration that corresponds toregulatory guidelines after the refrigerant leak signal 132 is no longerdetected. The compressor output signal 136 corresponds to the operationof the compressors 72, and the counter value 138 corresponds to thecounter hardware logic 84 (e.g., 16-bit down-counter with preload). Thecounter value corresponds to the regulatory guidelines for delay time tomaintain refrigerant leak mitigation actions.

Referring now to the graphical representation 130, the hardware logic 84may receive the refrigerant leak signal 132 at time 140, indicating thata refrigerant leak has occurred in the HVAC system. In response to therefrigerant leak signal 132 being high, the hardware logic 84 may enablethe leak override signal 134 to go high, which in turn activatesmultiple mitigation elements (e.g., commands to activate air supply fan32 and turn off electrical components of the refrigerant system). Forexample, in response to the leak override signal 134 being high (e.g.,signal is present), the hardware logic 84 may control multiplecomponents of the HVAC system including one or more compressors 72, oneor more heaters, and one or more supply fans 32 to perform mitigationoperations (e.g., turn off and/or turn on).

For example, after receiving the high leak override signal 134, at thetime 140, the hardware logic 84 may cause the compressor output signal136 to go low, which may cause the compressor 72 to deactivate. At time142 the refrigerant leak may no longer be present and the refrigerantleak signal 132 may no longer be received (e.g., signal value is low).The removal of the refrigerant leak signal 132 may cause the countervalue to begin counting down (e.g., according to the regulationrequirements for the delay period for mitigation actions to continueafter refrigerant leak is no longer present) at the time 142. Thecompressor output signal 136 may remain low and the leak override signal134 value may remain high while the counter value 138 is counting down.As such, the time delays may meet the ASHRAE 15-2019 fault standard thatspecifies that the compressor 72 is to remain off for at least fiveminutes after the refrigerant leak signal 132 was received by thehardware logic 84.

At time 144, the counter value 138 may have counted down to expiration.In response to the counter value reaching zero (e.g., delay time periodcompleted), the leak override signal 134 will no longer be active (e.g.,go to low/zero voltage value) and the compressor 72 will be activatedvia the compressor output signal 136 becoming active (e.g., highvoltage) at time 144.

Further, at time 146 the refrigerant leak signal 132 may become activeagain (e.g., leak detected) for a short time period. In response to therefrigerant leak signal 132 becoming active, the hardware logic 84 maycause the leak override signal 134 to become active and the compressoroutput signal 136 to become inactive. As a result, the compressor 72 mayturn off.

The counter value 138, at the time 147, will begin counting down untilit expires or the refrigerant leak signal 132 returns. For instance, attime 148, the refrigerant leak signal 132 may become active again.However, since the counter value 138 did not expire, the hardware logic84 continued to produce the leak override signal 134. At time 148, thecounter value 138 may reset and remain high until the refrigerant leaksignal 132 is no longer active.

At time 150, the refrigerant leak signal 132 may no longer be active. Inresponse to the refrigerant leak signal 132 no longer being active, thecounter value 138 may begin counting down for the delay time period. Inadditional, the leak override signal 134, which causes the compressoroutput signal 136 to be low, will remain active during the countdownperiod.

The refrigerant leak signal 132 enables the counter value 138 to be setand the counter value 138 will begin counting down when the refrigerantleak signal 132 is no longer active (e.g., no refrigerant leak isdetected). The leak override signal 134 will remain active until thecounter value 138 has reached zero and will enable the compressor outputsignal 136 to be low for the duration the leak override signal is high134 via the hardware logic 84. This enables the time delay to beimplemented utilizing the refrigerant leak signal 132.

The signals discussed above may be transmitted and received via thehardware logic 84 that may be part of the control board 82. This enablesmitigation efforts to be met via use of the hardware logic 84 elementswithout the need for software control programs.

With the foregoing in mind, FIG. 7A is an example schematic diagram ofcomponents of control logic including a counter pre-set and clockcomponent for a refrigerant leak detection and mitigation system, inaccordance with present techniques. The leak mitigation hardware controllogic 130 may function to turn off compressors and heaters and activatean air supply fan for a specified delay period according to industrystandards (e.g., ASHRAE 15-2019) in response to a leak detection signal(e.g., refrigerant leak signal 132) being received from a refrigerantsensor detector.

The leak mitigation hardware control logic 130 may perform mitigationmeasures when a reference detection signal (e.g., REF_DET 132),indicating a refrigerant leak, is received at the counter pre-set logic166. The counter pre-set logic 166 may include inputs [L15:L0] 172. Therefrigerant leak signal 134 enables the loading of the counter pre-setvalues [L15:L0] 172, which establishes the override latch time (e.g.,value calculated based on the clock frequency). The refrigerant leaksignal 132 is loaded into the [L15:L0] 172 inputs via the circuitryconnection. The [L15:L0] 172 inputs generate the [S15: S0] 174 and[R15:R0] 176 outputs via each of the [L15:L0] inputs being sent intomultiple AND logic gates with the reference detection signal 132 togenerate the [S15:S0] (e.g. set value) 174 and [R15:R0] 176 outputs. Thehardware control logic 130 also includes a counter signal 158 generatedby the oscillator clock and clock divider logic circuitry 160. The fiveminute standard according to the ASHRAE-2019 regulatory guidelines maybe specified, but more clock dividers may be added to account foradditional time frames.

With the foregoing in mind, FIG. 7B is an example schematic diagram ofcomponents of control logic including a counter component for arefrigerant leak detection and mitigation system, in accordance withpresent techniques. As detailed above, the counter pre-set 166 circuitryutilizes the refrigerant leak signal 132 and the [L15:L0] 172 signals togenerate the [S15: S0] 174 and [R15:R0] 176 signals that are able topre-set the 16-bit down counter with pre-load 162 through theasynchronous inputs of the SR-type flip-flops utilized to implement thedown counter. The 16 bit down counter with pre-load 162 includes 16connected J-K flip flops that include the [S15: S0] 174 and [R15:R0] 176signal inputs. The [S15:S0] 174 and [R15:R0] 176 signal inputs set theJ-K flips flops. When the J-K flip flops inputs have an active signalthey will not begin counting down regardless of [Q15:Q0] 178 signaloutputs. This enables the counter to not begin counting down until the[S15:S0] 174 and [R15:R0] 176 signal inputs are no longer activeregardless of the clock [Q15:Q0] 178 signal outputs.

Based on the above, FIG. 7C is an example schematic diagram ofcomponents of control logic including output lockout logic componentsfor a refrigerant leak detection and mitigation system, in accordancewith present techniques. The [Q15:Q0] 178 signal outputs of the 16-bitdown counter with pre-load 162 are sent into the clock enable 168 andleak override logic circuitry 170. With a non-zero [Q15:Q0] 178 outputvalue, the counter clock input is enabled by the clock logic circuitry168. In other embodiments, the counter may include an up-counting deviceor re-triggerable monostable multi-vibrator circuit instead of a downcounter that may use a resister and capacitor to set the timing insteadof the bits counter. The counter enables 168 the logic circuitry outputsignal of the counter 158 to be sent into the input of the 16-bit downcounter with pre-load 162 and the leak over signal 134 output signal ofthe leak override logic circuitry 170 to be active. The clock enablelogic circuitry 168 includes the [Q15:Q0] 178 input into four OR logicgates with input corresponding to [Q15:Q12], [Q11:Q8], [Q7:Q4], and[Q3:Q0]. The outputs of the four OR logic gates are coupled to a singleOR logic gate. The output of the single OR logic gate is coupled to afinal AND logic gate that activates the counter clock 156 signal. Theother input of the final AND logic date is the counter signal 158generated by the oscillator clock and clock divider logic circuitry 160.The five minute standard according to the ASHRAE-2019 regulatoryguidelines may be specified, but more clock dividers may be added toaccount for additional time frames. It should be understood thatalthough the J-K flip flops are utilized any type of flip flop thatprovides asynchronous inputs may be implemented.

The [Q15:Q0] 178 output values are also sent to the leak override logiccircuitry 170 which include multiple AND gates and a final NAND gateoutput coupled to the leak override signal 134 output that enables theleak override signal 134 to remain active until the [Q15:Q0] 178 outputvalues are de-incremented to zero. The value of [Q15:Q0] 178 will notbegin de-incrementing until the counter reaches zero, which causes thecounter clock 158 signal to be disabled and the leak over signal 134 toreturn to zero.

The leak override signal 134 is sent to an input of the output logiccircuitry 164. The output logic circuitry directs the leak overridesignal 134 to the input of the AND logic gates also coupled to thecompressor output signals 136 (e.g., C1_OUT, C2_OUT), heater outputsignals 184 (H1_OUT, H2_OUT), the electronic load regenerative heatingoutput signal 188 (e.g., AUX_HGT_DRV), and a supply air fan outputsignal 190 (e.g., supply air fan). The input for the compressor outputsignals 180 AND gate is the leak override signal 176 and the compressorinput signal 154 which are input to an AND gate and connected to anadditional AND gate along with the input of the high-pressure switchinput signal. The same logic circuitry is applied to the heater outputsignal 184 and the electronic load regenerative heating output signal188. For example, the compressor may be on and the compressor activationsignal may be high. The active leak override signal 134 is inverted bythe logic gate and the result is a low output sent to the final ANDlogic gate for the compressor output signal 186 resulting in thecompressor signal going low and the compressor 72 being powered offduring the duration of the leak override signal being high 134.

The fan activation signal input 154 is input to an OR logic gate alongwith the leak override 134 signal. This enables the fan output signal190 (e.g., fan output) to remain high when a refrigerant leak isdetected through the time period specified by the clock logic 160. Theoutput lockout logic 164 may include other override controls thatcorrespond to high-pressure switches for the compressor. The one or morehigh-pressure switch signals 180 are input at the AND gate coupled tothe compressor signal output 136 and may result in the compressor 72turning off if a high-pressure switch trip is detected. Although oneconfiguration of output lockout logic 164 is detailed above, multipleconfigurations may be implemented to implement the mitigation standards.

Based on the foregoing, FIG. 8 is an example schematic diagram of theoutput lockout logic of the control logic of FIG. 7 , in accordance withthe present techniques. The high leak override signal 134 may enable allthe compressors 72 and heaters to be turned off during the time periodthat the reference detection signal 132 signal is received and the delayperiod after the reference detection signal 132 is no longer received atthe control logic 130.

The refrigerant leak signal 132 may be coupled to the clock enable 168and the 16-bit down counter with pre-load 162 circuitry as mentionedabove in FIG. 8 . The leak override signal 134 signal may be activatedin response to the reference detection signal 132 signal being receivedand may be coupled to the inputs of the compressor output logic 136 andthe heater output logic 184 respectively through two 3-bit Look-up-Table192 for each of the compressor output logic 136 and three 2-bit LUT 194for each of the heater output logic 184. The two 3-bit LUTs 192 mayreceive inputs from each of the compressor drive signals 154respectively which receive inputs from the input control signals 200,the leak override signal 134, and the high-pressure switch signals 180respectively. The three 2-bit LUTs 194 may each receive the input of theheater drive signals 154 or the electronic load regenerative heatingdrive signal and may receive the leak override signal 134 input.

The 3-bit LUTs 192 are coupled to the input for the high-pressure switchsignals 180, 181 that may detect if a pressure switch override tripsignal 202, 204 has occurred and results in the compressor 72corresponding to the override to be powered off according to regulatorystandards. The 3-bit LUTs 192 and 2-bit LUTs 182 may be set tocorrespond to the hardware logic 84 discussed above in the logic outputarray 164 of FIG. 8 . The 3-bit LUTs 192 may include the hardware logic84 that utilizes logic gates to allow a high compressor signal outputwhen the leak override signal 176 signal is low and the high-pressuresignal switch 180 is high. The two-bit LUTs may be include the hardwarelogic 84 that enables high output signals when the drive signals 154 arehigh and the received leak override signal at the input is low. Thisenables multiple compressor and heaters to be turn off in response to arefrigerant leak being detected to comply with regulatory standards.

The input logic corresponding to the supply fan output signal 190 is a2-L3 OR logic gate that enables the supply fan to be active when asignal is received at the logic gate by either the fan drive activationsignal 154 and/or the leak override signal 134. This enables the supplyfan to be active 196 according to leak mitigation regulatory standards.

The output circuitry may be implemented in the architecture describedabove, or any other suitable architecture to implement the lockoutmethod. The input signals 154 for all the compressors 72 and heaters,may be coupled to the logic circuit as discussed above. The controllingelements are the leak override signal 134 signal which may remain on forthe delay time period after the refrigerant leak signal 132 is no longerreceived.

Although the foregoing description of the example schematic diagrams forcontrol logic is described as being used to implement the techniquesdescribed herein, it should be noted that these schematic diagrams areprovided for exemplary purposes. That is, the hardware logic 84 toimplement the above-referenced techniques may include otherarrangements, logic elements, and the like. Moreover, it should be notedthat, in some embodiments.

While only certain features and embodiments of the present disclosurehave been illustrated and described, many modifications and changes mayoccur to those skilled in the art, such as variations in sizes,dimensions, structures, shapes and proportions of the various elements,values of parameters, mounting arrangements, use of materials,orientations, and so forth, without materially departing from the novelteachings and advantages of the subject matter recited in the claims.The order or sequence of any process or method steps may be varied orre-sequenced according to alternative embodiments. It is, therefore, tobe understood that the appended claims are intended to cover all suchmodifications and changes as fall within the true spirit of thedisclosure. Furthermore, in an effort to provide a concise descriptionof the embodiments, all features of an actual implementation may nothave been described, such as those unrelated to the presentlycontemplated best mode of carrying out the disclosure, or thoseunrelated to enabling the claimed features. It should be appreciatedthat in the development of any such actual implementation, as in anyengineering or design project, numerous implementation specificdecisions may be made. Such a development effort might be complex andtime consuming, but would nevertheless be a routine undertaking ofdesign, fabrication, and manufacture for those of ordinary skill havingthe benefit of this disclosure, without undue experimentation.

The techniques presented and claimed herein are referenced and appliedto material objects and concrete examples of a practical nature thatdemonstrably improve the present technical field and, as such, are notabstract, intangible or purely theoretical. Further, if any claimsappended to the end of this specification contain one or more elementsdesignated as “means for [perform]ing [a function] . . . ” or “step for[perform]ing [a function] . . . ,” it is intended that such elements areto be interpreted under 35 U.S.C. 112(f). However, for any claimscontaining elements designated in any other manner, it is intended thatsuch elements are not to be interpreted under 35 U.S.C. 112(f).

1. A system, comprising: a heating, ventilation, and air conditioning(HVAC) system; and a plurality of circuit components configured to:determine that a refrigerant leak is present within the HVAC systembased on a signal; send a first set of instructions to a first set ofcontrol systems associated with one or more fans in response to therefrigerant leak being present, wherein the first set of instructions isconfigured to cause one or more fans to activate; determine that therefrigerant leak signal is no longer present based on the signal;initiate a counter to detect when a period of time has passed inresponse to determining that the refrigerant leak signal is no longerpresent; and send a second set of instructions to the first set ofcontrol systems in response to the counter indicating that the period oftime has passed, wherein the second set of instructions is configured tocause the one or more fans to return to base operating conditions. 2.The system of claim 1, wherein the plurality of circuit components isconfigured to send a third set of instructions to a second set ofcontrol systems associated with one or more components within the HVACsystem in response to the refrigerant leak being present, wherein thethird set of instructions is configured to cause the one or morecomponents to deactivate.
 3. The system of claim 2, wherein the one ormore components comprise one or more heaters, one or more compressors,or any combination thereof.
 4. The system of claim 2, wherein theplurality of circuit components is configured to send a fourth set ofinstructions to the second set of control systems in response to thecounter indicating that the period of time has passed, wherein the thirdset of instructions is configured to cause the one or more components toreturn to base operating conditions.
 5. The system of claim 1, whereinthe plurality of circuit components is configured to: produce a leakoverride signal in response to receiving the signal; remove the leakoverride signal after the counter indicates that the period of time haspassed; and send the second set of instructions in response to the leakoverride signal being removed.
 6. The system of claim 1, wherein theplurality of circuit components comprise a discrete logic device, acomplex programmable logic device (CLPD), a field-programmable gatearray (FPGA), an application-specific integrated circuit (ASIC), or anycombination thereof.
 7. The system of claim 1, wherein the countercomprises a 16-bit down counter with pre-load functionality.
 8. Thesystem of claim 7, wherein the plurality of circuit components comprisean oscillator clock component.
 9. The system of claim 8, wherein theplurality of circuit components are configured to send an output of theoscillator clock component to the 16-bit down counter in response toreceiving the signal.
 10. A set of hardware components configured to:receive a refrigerant leak signal from a sensor assembly; transmit aleak detection signal and pre-set a counter in response to receiving therefrigerant leak signal; determine that the refrigerant leak signal isno longer being received; and stop transmitting the leak detectionsignal after a delay period of time after the refrigerant leak signal isno longer received and in response to the counter indicating that thedelay period of time has passed.
 11. The set of hardware components ofclaim 10, wherein the sensor assembly comprises a power source, acontroller, and one or more refrigerant concentration sensors.
 12. Theset of hardware components of claim 10, wherein the sensor assemblyoutput is coupled to hardware logic.
 13. An integrated circuitcomprising a plurality of circuit components configured to: determinethat a signal corresponding to a refrigerant leak is present; send afirst set of instructions to a first set of control systems associatedwith one or more fans in response to the refrigerant leak being present,wherein the first set of instructions is configured to cause one or morefans to activate; determine that the refrigerant leak signal is nolonger present based on the signal; initiate a counter to detect when aperiod of time has passed in response to determining that therefrigerant leak signal is no longer present; and send a second set ofinstructions to the first set of control systems in response to thecounter indicating that the period of time has passed, wherein thesecond set of instructions is configured to cause the one or more fansto return to base operating conditions.
 14. The integrated circuit ofclaim 13, wherein the plurality of circuit components are configured tosend a third set of instructions to a second set of control systemsassociated with one or more components in response to the refrigerantleak being present, wherein the third set of instructions is configuredto cause the one or more components to deactivate.
 15. The integratedcircuit of claim 14, wherein the one or more components comprise one ormore heaters, one or more compressors, or any combination thereof. 16.The integrated circuit of claim 14, wherein the plurality of circuitcomponents comprises an oscillator clock component.
 17. The integratedcircuit of claim 16, wherein the plurality of circuit components isconfigured to send an output of the oscillator clock component to a16-bit down counter in response to receiving the signal.
 18. A methodcomprising: determining, via a plurality of circuit components, that asignal corresponding to a refrigerant leak is present; sending, via theplurality of circuit components, a first set of instructions to a firstset of control systems associated with one or more fans in response tothe refrigerant leak being present, wherein the first set ofinstructions is configured to cause one or more fans to activate;determining, via the plurality of circuit components, that therefrigerant leak signal is no longer present based on the signal;initiating, via the plurality of circuit components, a counter to detectwhen a period of time has passed in response to determining that therefrigerant leak signal is no longer present; and sending, via theplurality of circuit components, a second set of instructions to thefirst set of control systems in response to the counter indicating thatthe period of time has passed, wherein the second set of instructions isconfigured to cause the one or more fans return to base operatingconditions.
 19. The method of claim 18, comprising initiating thecounter to begin counting down from an initial value in response to therefrigerant leak signal no longer being present.
 20. The method of claim19, comprising resetting the counter to the initial value in response todetermining that the refrigerant leak signal is present before theperiod of time has passed.